微囊藻毒素在鲋鱼体内生物富集及其体内的抗氧化反应

Bioaccumulation of microcystin and antioxidative response in Carassius auratus L

为了解微囊藻毒素在鲋鱼Carassius auratus L.体内生物富集作用,用LC/MS监测不同时间的鲋鱼肝脏、肌肉,以及饲养用水中痕量的微囊藻毒素。结果显示,肌肉组织中MC-RR和MC-LR的含量在18d时达到峰值,分别为7.87ng·g-1和2.18ng·g-1;而肝脏组织中MC-RR和MC-LR的含量在鲋鱼暴露9天时达到最高值,分别为25.30ng·g-1和33.27ng·g-1。研究结果支持肝脏组织是MCs的主要靶向器官,并且表明肝脏组织对MC-LR的富集量远大于MC-RR,而肌肉组织更易于积累MC-RR。文章还研究了鲋鱼体内的抗氧化酶(SOD、CAT、GST、GR酶)的活性变化,对MCs介导的氧化胁迫进行了评估。通过分别测定暴露不同时间点(3、9、18d)肝脏和肌肉组织中的抗氧化酶的活性,发现它们的活性与组织中MCs的含量基本呈正相关,可能对MCs介导的氧化胁迫有缓解作用。以上表明,MCs能在鱼体内积累,抗氧化系统虽可缓解,但不能完全降解。因此食用被MCs污染的鱼类存在潜在的食品安全风险。

In order to investigate the bioaccumulation of microcystins（MCs） in Carassius auratus L., the level of MCs in liver, muscle and water was monitored by LC/MS at different time after exposure. The results indicated that the level of MC-RR and MC-LR was the highest in muscle on the 18th day after exposure, with each amount of 7.87 ng/g and 2.18 ng/g, and reached the peak in liver on the 9th day with the amount of 25.30 ng/g and 33.27 ng/g respectively. The results showed that the bioaccumulation of MCs is prone to occur in liver than in muscle. The level of MC-LR was higher than MC-RR in liver, and the MC-RR was prone to accumulate in muscle. The oxidative stress of fish mediated by MCs was also evaluated by analyzing the activities of several antioxidases such as superoxide dismutase （SOD）, catalase （CAT）, Glutathione-S-transferase （GST） and glutathione reductase （GR）. The activities of these antioxidases in liver and muscle were measured after exposing to MCs after 3, 9 and 18 days. It was demonstrated that the level of MCs was basically positive-correlated to the activity of antioxidase, which probably released the oxidative stress mediated by MCs. Overall, fish can accumulate microcystins and make respose to the toxicity with antioxidative system, but can not degrade the MCs completely. So it should be noted that people with whose diets contain the fish exposed to MCs, would potentially suffer the health threaten.